Integrated process for the production of z-1,1,1,4,4,4-hexafluoro-2-butene

ABSTRACT

Disclosed is a process for the preparation of cis-1,1,1,4,4,4-hexafluoro-2-butene comprising contacting 1,1,1-trifluorotrichloroethane with hydrogen in the presence of a catalyst comprising ruthenium to produce a product mixture comprising 1316mxx, recovering said 1316mxx as a mixture of Z- and E-isomers, contacting said 1316mxx with hydrogen, in the presence of a catalyst selected from the group consisting of copper on carbon, nickel on carbon, copper and nickel on carbon and copper and palladium on carbon, to produce a second product mixture, comprising E- or Z-CFC-1326mxz, and subjecting said second product mixture to a separation step to provide E- or Z-1326mxz. The E- or Z-1326mxz can be dehydrochlorinated in an aqueous basic solution with an alkali metal hydroxide in the presence of a phase transfer catalyst to produce hexafluoro-2-butyne, which can then be selectively hydrogenated to produce Z-1,1,1,4,4,4-hexafluoro-2-butene using either Lindlar&#39;s catalyst, or a palladium catalyst further comprising a lantanide element or silver.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. Ser. No. 15/699,067filed Sep. 8, 2017, which is a divisional application of Ser. No.15/114,944 filed Feb. 6, 2015; which is a 371 of International PatentApplication PCT/US15/14783 filed Feb. 6, 2015; which claims the benefitof priority of U.S. Provisional Application No. 61/937,109 filed Feb. 7,2014.

BACKGROUND INFORMATION Field of the Disclosure

This disclosure relates in general to methods of synthesis offluorinated olefins.

Description of the Related Art

The fluorocarbon industry has been working for the past few decades tofind replacement refrigerants for the ozone depletingchlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) beingphased out as a result of the Montreal Protocol. The solution for manyapplications has been the commercialization of hydrofluorocarbon (HFC)compounds for use as refrigerants, solvents, fire extinguishing agents,blowing agents and propellants. These new compounds, such as HFCrefrigerants, HFC-134a and HFC-125 being the most widely used at thistime, have zero ozone depletion potential and thus are not affected bythe current regulatory phase-out as a result of the Montreal Protocol.

In addition to ozone depleting concerns, global warming is anotherenvironmental concern in many of these applications. Thus, there is aneed for compositions that meet both low ozone depletion standards aswell as having low global warming potentials. Certain hydrofluoroolefinsare believed to meet both goals. Thus there is a need for manufacturingprocesses that provide halogenated hydrocarbons and fluoroolefins thatcontain no chlorine that also have a low global warming potential.

SUMMARY

In one embodiment, disclosed is a part of a process for the preparationof cis-1,1,1,4,4,4-hexafluoro-2-butene comprising contacting1,1,1-trifluorotrichloroethane with hydrogen in the presence of acatalyst comprising ruthenium to produce a product mixture comprising1316mxx, recovering said 1316mxx as a mixture of Z- and E-isomers,contacting said 1316mxx with hydrogen, in the presence of a catalystselected from the group consisting of copper on carbon, nickel oncarbon, copper and nickel on carbon and copper and palladium on carbon,to produce a second product mixture, comprising E- or Z-CFC-1326mxz, andsubjecting said second product mixture to a separation step to provideE- or Z-1326mxz.

In another embodiment, disclosed is a process for the preparation offluorine-containing olefins comprising contacting a chlorofluoroalkenehaving the formula E- and Z-CF₃CCl═CClCF₃ with hydrogen in the presenceof a catalyst comprising copper and palladium on a support, at atemperature of from about 150° C. to 250° C., to produce a productmixture comprising a fluorine-containing olefin having the formula E- orZ-CF₃CH═CClCF₃, or a mixture thereof, wherein the conversion ofZ-CF₃CCl═CClCF₃ is at least 80% of the conversion of the Z-isomer, andthe selectivity to the two isomers of CF₃CH═CClCF₃ is at least 85%.

In yet another embodiment, disclosed is a process for coupling achlorofluorocarbon comprising contacting1,1,1-trichloro-2,2,2-trifluoroethane with hydrogen in the presence of acatalyst comprising ruthenium on a silicon carbide support, to produce aproduct mixture comprising 1,1,1,4,4,4-hexafluoro-2,3-dichloro-2-buteneand hydrogen chloride, and recovering the1,1,1,4,4,4-hexafluoro-2,3-dichloro-2-butene.

In yet another embodiment, disclosed is a process for the preparation ofE- or Z-HFO-1336mzz comprising contacting hexafluoro-2-butyne withhydrogen at a ratio of 1:0.025 to 1:1.1 (molar ratio ofhexafluoro-2-butyne in a reactor in the presence of a metallic catalystat a temperature sufficient to cause hydrogenation of the triple bond ofthe hexafluoro-2-butyne producing a product stream comprisingHFO-1336mzz and unreacted hexafluoro-2-butyne, wherein the catalyst is ametallic catalyst at a concentration of 100-5000 ppm dispersed overaluminum oxide, silicon carbide, or titanium silicates with a Ag orlanthanide poison, wherein the recycle ratio of reactant to product isbetween 1 and 9.

The foregoing general description and the following detailed descriptionare exemplary and explanatory only and are not restrictive of theinvention, as defined in the appended claims.

DETAILED DESCRIPTION

Disclosed is a process for the preparation ofcis-1,1,1,4,4,4-hexafluoro-2-butene comprising contacting1,1,1-trifluorotrichloroethane with hydrogen in the presence of acatalyst comprising ruthenium to produce a product mixture comprising1316mxx, recovering said 1316mxx as a mixture of Z- and E-isomers,contacting said 1316mxx with hydrogen, in the presence of a catalystselected from the group consisting of copper on carbon, nickel oncarbon, copper and nickel on carbon and copper and palladium on carbon,to produce a second product mixture, comprising E- or Z-CFC-1326mxz, andsubjecting said second product mixture to a separation step to provideE- or Z-1326mxz. The E- or Z-1326mxz can be dehydrochlorinated in anaqueous basic solution with an alkali metal hydroxide in the presence ofa phase transfer catalyst to produce hexafluoro-2-butyne, which can thenbe selectively hydrogenated to produce Z-1,1,1,4,4,4-hexafluoro-2-buteneusing either Lindlar's catalyst, or a palladium catalyst furthercomprising a lanthanide element or silver.

In another embodiment, disclosed is a process for the preparation offluorine-containing olefins comprising contacting a chlorofluoroalkenehaving the formula E- and Z-CF₃CCl═CClCF₃ with hydrogen in the presenceof a catalyst comprising copper and palladium on a support, at atemperature of from about 150° C. to 250° C., to produce a productmixture comprising a fluorine-containing olefin having the formula E- orZ-CF₃CH═CClCF₃, or a mixture thereof, wherein the conversion ofZ-CF₃CCl═CClCF₃ is at least 80% of the conversion of the Z-isomer, andthe selectivity to the two isomers of CF₃CH═CClCF₃ is at least 85%.

In yet another embodiment, disclosed is a process for coupling achlorofluorocarbon comprising contacting1,1,1-trichloro-2,2,2-trifluoroethane with hydrogen in the presence of acatalyst comprising ruthenium on a silicon carbide support, to produce aproduct mixture comprising 1,1,1,4,4,4-hexafluoro-2,3-dichloro-2-buteneand hydrogen chloride, and recovering the1,1,1,4,4,4-hexafluoro-2,3-dichloro-2-butene.

In yet another embodiment, disclosed is a process for the preparation ofE- or Z-HFO-1336mzz comprising contacting hexafluoro-2-butyne withhydrogen at a ratio of 1:0.025 to 1:1.1 (molar ratio ofhexafluoro-2-butyne in a reactor in the presence of a metallic catalystat a temperature sufficient to cause hydrogenation of the triple bond ofthe hexafluoro-2-butyne producing a product stream comprisingHFO-1336mzz and unreacted hexafluoro-2-butyne, wherein the catalyst is ametallic catalyst at a concentration of 100-5000 ppm dispersed overaluminum oxide, silicon carbide, or titanium silicates with a Ag orlanthanide poison, wherein the recycle ratio of reactant to product isbetween 1 and 9.

Many aspects and embodiments have been described above and are merelyexemplary and not limiting. After reading this specification, skilledartisans appreciate that other aspects and embodiments are possiblewithout departing from the scope of the invention.

Other features and benefits of any one or more of the embodiments willbe apparent from the following detailed description, and from theclaims.

As used herein, chlorofluorocarbon is a C2, C3 or C4 alkane substitutedcompletely with chlorine and fluorine, wherein all the chlorinesubstituents are on one terminal carbon of the molecule. Representativechlorofluorocarbons include 1,1,1-trichlorotrifluoroethane,1,1,1-trichloro-pentafluoropropane, and 1,1,1-trichlorooctafluorobutane.

In one embodiment, disclosed is a process for the preparation ofZ-HFO-1336mzz comprising dimerizing CFC-113a in the presence of aruthenium catalyst to produce Z- and E-CFC-1316mxx, hydrogenatingCFC-1316mxx in the presence of a catalyst to produce HCFO-1326mxz,dehydrochlorinating this to produce hexafluoro-2-butyne, and thenhydrogenating the hexafluoro-2-butyne to produce Z-HFO1336mzz.

It has been previously reported, that two and three carbonchlorofluorocarbons can be dimerized to produce 4 carbon and 6 carbonchlorofluoroolefins, such as F1316mxx and F151-10mcxx, through reactionwith hydrogen over a supported ruthenium catalyst. See U.S. Pat. No.5,919,994. The chlorofluorocarbons included CCl₃CF₃ and CCl₃CF₂CF₃. Theruthenium catalyst could be supported on fluorided alumina, aluminumfluoride and fluorides of at least one metal selected from the groupconsisting of Zn, Mg, Ca, Ba, Y, Sm, Eu and Dy. Among the by-productsproduced were moderate amounts of two carbon compounds such as1,1,1-trifluoroethane (HFC-143a), 1,1,1-trifluoro-2-chloroethane(HCFC-133a) or 1,1,1-trifluoro-2,2-dichloroethane (HCFC-123a),presumably formed from hydrogenolysis of one or more chlorinesubstituents. The dimerization produces 2 moles of HCl for each mole ofCFC-113a reacted.

It has now been found that, while such catalysts are useful forhydrogenolysis reactions, they are less than optimal for dimerizationreactions of this type. In particular, it has been observed thatcatalyst samples after use in coupling reactions for some period of timetypically exhibit significant decreases in crush strength. In addition,for these reactions which produce hydrogen chloride as a reactionproduct from the coupling process, when the reactor effluent is scrubbedupon exiting the reactor, there is evidence of hydrogen fluoride inaddition to hydrogen chloride, presumably from halogen exchange with thesupport. This would also necessitate the use of corrosion resistantmaterials of construction for the reactor materials.

It has now been found that ruthenium catalysts deposited on a siliconcarbide support provide a catalyst which has higher crush strength, evenafter prolonged use. The ruthenium can be deposited on the support bytechniques well known in the art, such as impregnation, or evaporationfrom solution. In one embodiment, the concentration of ruthenium on thesupport is typically in the range of from 0.1 weight percent to 5 weightpercent. In another embodiment, the concentration of ruthenium on thesupport is from 0.25 weight percent to 3 weight percent. In yet anotherembodiment, the concentration of ruthenium on the support is from 0.5weight percent to 2 weight percent. The crush strength of 2% rutheniumon calcium fluoride was observed to decrease from 6.6 pounds to 1.8pounds after use in a reactor to convert 113a to 1316mxx for 12 hours.By comparison, the crush strength of a 1% ruthenium catalyst on siliconcarbide was 45.1 pounds before use, and essentially unchanged after usefor 12 hours.

The ruthenium can be deposited from any soluble ruthenium compound,including for example ruthenium halides, such as ruthenium chloride, orruthenium nitrosyl nitrate.

The dimerization reaction in one embodiment is typically conducted at atemperature of from 150° C. to 300° C. In another embodiment, thedimerization reaction is conducted at from 150° C. to 240° C. In yetanother embodiment the dimerization reaction is conducted at from 150°C. to 190° C. In one embodiment, the mole ratio of hydrogen to CFC-113acan be from 4:1 to 20:1. In another embodiment, the mole ratio ofhydrogen to CFC-113a can be from 12:1 to 20:1. After scrubbing outhydrogen chloride, the product mixture comprising Z- and E-CFC-1316mxxcan be recovered by distillation. Analysis of the scrubbing solution forhalogen by ion chromatography indicates that for catalysts supported onCaF2 that between 2.3% and 8.3% of the halogen in the scrubber solutionis fluoride. Similar analysis of the scrubber solution for reactions runwith catalysts supported on SiC find 0.6% of the halogen as fluoride.

Step II

Chlorofluoroalkenes can be converted to fluoroalkenes, fluoroalkynes ormonochlorofluoroalkenes in the presence of hydrogen using catalystscontaining of copper on carbon, copper on calcium fluoride, palladium onbarium sulfate, palladium/barium chloride on alumina, Lindlar catalyst(palladium on CaCO₃, poisoned with lead), palladium on calcium fluoridepoisoned with lead, copper and nickel on carbon, nickel on carbon,nickel on calcium fluoride, copper/nickel/chromium on calcium fluorideand unsupported alloys of copper and nickel. Other catalysts includecatalysts comprising copper and nickel, nickel and chromium or copper,nickel and chromium. Still other catalysts include combinations ofcopper, nickel or chromium further comprising alkali metals such aspotassium, cesium, rubidium or combinations thereof. Such catalysts maybe supported on supports such as metal fluorides, alumina, and titaniumdioxide, or unsupported.

Such catalysts can have relatively low rates of reactivity resulting inthe need for large reactors to produce significant quantities on acommercial scale. In addition, chlorofluoroolefin 1316mxx is typicallyfound as a mixture of the E- and Z-isomers, in a ratio of from about 3:2to about 2:1. In practice, when using catalysts of copper supported oncarbon or copper and nickel supported on carbon, the E-isomer issignificantly more reactive than the Z-isomer. In order to obtainadequate conversion of the Z-isomer to HCFO-1326mxz, reactors need to besized and conditions set to achieve adequate conversion of both thefaster and slower reacting isomers.

Further, in order to obtain acceptable conversions, and reaction rates,with catalysts comprising copper, or copper and nickel, reactiontemperatures of 300° C. and higher were typically required. However,copper metal begins to sublime at approximately 250° C., such thatoperating a reactor with a catalyst comprised of copper on a support, orcopper and nickel on a support at temperature of 300° C. or higher wouldresult in a coating of copper being deposited on the interior of thedownstream components of the reactor system. Thus such a system andcatalyst is not practical for use in a long term commercial productionfacility.

It has now been found that use of catalysts comprising copper combinedwith small amounts of palladium and supported on carbon can producesignificant and unexpected improvements in both rate of reaction andselectivity. In one embodiment, the catalyst comprises from 0.1 to 1.0weight percent palladium. In one embodiment, the catalyst comprises from0.1 to 20 weight percent copper. In another embodiment, the catalystcomprises from 0.6 to 5.0 weight percent copper.

In one embodiment, the ratio of reactivity of the Z-isomer to theE-isomer is less than 2.5:1. In another embodiment, the ratio ofreactivity of the Z-isomer to the E-isomer is less than 2.0:1. In yetanother embodiment, the ratio of reactivity of the Z-isomer to theE-isomer is less than 1.5:1.

In one embodiment, the contact time for the process ranges from about 2to about 120 seconds. In another embodiment, the contact time for theprocess ranges from 15 to 60 seconds.

In one embodiment, the ratio of hydrogen to chlorofluoroalkene is fromabout 1:1 to about 4:1. In another embodiment, the ratio of hydrogen tochlorofluoroalkene is from about 1:1 to about 2:1.

In one embodiment, the process for preparation of fluorine-containingolefins comprises reacting a chlorofluoroalkene with hydrogen in areaction vessel constructed of an acid resistant alloy material. Suchacid resistant alloy materials include stainless steels, high nickelalloys, such as Monel, Hastelloy, and Inconel. In one embodiment, thereaction takes place in the vapor phase.

In one embodiment, the temperature at which the process is run may be atemperature sufficient to cause replacement of the chlorine substituentswith hydrogen. In another embodiment, the process is conducted at atemperature of from about 150° C. to about 300° C.

In some embodiments, the pressure for the hydrodechlorination reactionis not critical. In other embodiments, the process is performed atatmospheric or autogenous pressure. Means may be provided for theventing of the excess pressure of hydrogen chloride formed in thereaction and may offer an advantage in minimizing the formation of sideproducts. In some embodiments, the process is conducted simply byflowing hydrogen and chlorofluoroalkene into the catalyst bed in areactor at a specified temperature. In some embodiments the process isconducted by flowing hydrogen, chlorofluoroalkene and a carrier gas intothe catalyst bed in the reactor. Examples of carrier gases include inertgases such as nitrogen, argon and helium.

Additional products of the reaction may include partiallyhydrodechlorinated intermediates; completely dechlorinated products,saturated hydrogenated compounds; various partially chlorinatedintermediates or saturated compounds; and hydrogen chloride (HCl). Forexample, wherein the chlorofluoroalkene is2,3-dichloro-1,1,1,4,4,4-hexafluoro-2-butene (CFC-1316mxx, E- and/orZ-isomers), the compounds formed in addition to E- and/orZ-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene (E- and/or Z-HFC-1326mxz) mayinclude, E- and/or Z-1,1,1,4,4,4-hexafluoro-2-butene (HFC-1336mzz),1,1,1,4,4,4-hexafluorobutane (HFC-356mff), pentafluorobutane (HFC-1345,different isomers), 2-chloro-1,1,1,4,4,4-hexafluorobutane (HFC-346mdf),and 1,1,1,4,4,4-hexafluoro-2-butyne (HFB).

Step III

Also disclosed herein is a process for producing hexafluoro-2-butynecomprising, reacting Z-1,1,1,4,4,4-hexafluoro-2-chloro-2-buteneHCFC-1326mxz) with an aqueous solution of an alkali metal hydroxide inthe presence of a quaternary alkylammonium salt having alkyl groups offrom four to twelve carbon atoms and mixtures thereof to produce amixture comprising hexafluoro-2-butyne, and recovering thehexafluoro-2-butyne, wherein the conversion ofZ-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene to hexafluoro-2-butyne is atleast 50% per hour.

Also disclosed is a process for producing hexafluoro-2-butynecomprising, reacting a fluorochloroolefin comprisingE-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene with an aqueous solution ofan alkali metal hydroxide in the presence of a quaternary alkylammoniumsalt which comprises at least one alkyl group of at least 8 carbons, andrecovering the hexafluoro-2-butyne, wherein the conversion ofE-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene to hexafluoro-2-butyne is atleast 15% per hour.

Also disclosed is a process for producing hexafluoro-2-butynecomprising, reacting a fluorochloroolefin comprising Z- andE-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene with an aqueous solution ofan alkali metal hydroxide in the presence of a quaternary alkylammoniumsalt having alkyl groups of from four to twelve carbon atoms, andmixtures thereof, and a non-ionic surfactant, and recovering thehexafluoro-2-butyne, and wherein the conversion of Z- orE-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene to hexafluoro-2-butyne is atleast 20% per hour.

Hydrofluorochloroolefin HCFC-1326mxz is an impurity in some schemes forthe synthesis of 1,1,1,4,4,4-hexafluoro-2-butene, which is of interestas a foam expansion agent. In other potential schemes, it can be anintermediate. One method of synthesis of HCFC-1326mxz is through thehydrogenation of 1,1,1,4,4,4-hexafluoro-2,3-dichloro-2-butene. Whateverthe method of synthesis, one typically obtains a mixture of the Z- andE-stereoisomers about the double bond. Unfortunately, it exhibits ratherhigh toxicity, so whether formed as an impurity, or as an intermediate,it is desirable to convert it into useful product in high yield.Dehydrochlorination would provide hexafluoro-2-butyne, which could behydrogenated to provide 1,1,1,4,4,4-hexafluoro-2-butene. In classicalorganic chemistry, the dehydrochlorination of vinyl chlorides to formacetylenes requires rather harsh conditions, such as very strong bases,such as sodium in liquid ammonia. It has been reported that highermolecular weight polyfluorinated vinyl chlorides can bedehydrohalogenated to alkynes using aqueous base at temperatures of from100-120° C. up to 200 or 250° C. At these temperatures however,hexafluoro-2-butyne would have too high a vapor pressure in a reactor,and be susceptible to degradation.

It has been found that Z- and E-1,1,1,4,4,4-hexafluoro-2-chloro-2-butenecan be dehydrochlorinated at temperatures well below 100° C. using anaqueous basic solution in combination with quaternary alkylammoniumsalts as a phase transfer catalyst.

As used herein, phase transfer catalyst is intended to mean a substancethat facilitates the transfer of ionic compounds into an organic phasefrom an aqueous phase or from a solid phase. The phase transfer catalystfacilitates the reaction of these dissimilar and incompatiblecomponents. While various phase transfer catalysts may function indifferent ways, their mechanism of action is not determinative of theirutility in the present invention provided that the phase transfercatalyst facilitates the dehydrochlorination reaction.

A phase transfer catalyst as used herein is a quaternary alkylammoniumsalt wherein the alkyl groups are alkyl chains having from four totwelve carbon atoms. In one embodiment, the quaternary alkyl ammoniumsalt is a tetrabutylammonium salt. The anions of the salt can be halidessuch as chloride or bromide, hydrogen sulfate, or any other commonlyused anion.

In another embodiment, the quaternary alkylammonium salt istrioctylmethylammonium chloride (Aliquat 336). In another embodiment,the quaternary alkylammonium salt is tetraoctylammonium chloride. In yetanother embodiment, the quaternary alkylammonium salt istetraoctylammonium hydrogen sulfate.

Other compounds commonly thought of as phase transfer catalysts in otherapplications, including crown ethers, cryptands or non-ionic surfactantsalone, do not have a significant effect on conversion or the rate of thedehydrochlorination reaction in the same fashion.

The Z- and E-isomers of 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene exhibitsignificantly different reactivities with respect todehydrochlorination, and have different requirements for what functionsas an effective phase transfer catalyst in this reaction.Dehydrochlorination of the Z-isomer CF₃CCl═CHCF₃ can be effected withquaternary alkylammonium salts wherein the alkyl groups are alkyl chainshaving from four to twelve carbon atoms. The anions of the salt can behalides such as chloride or bromide, hydrogen sulfate, or any othercommonly used anion. In one embodiment, the quaternary alkyl ammoniumsalt is a tetrabutylammonium salt. In another embodiment, the quaternaryalkylammonium salt is a tetrahexylammonium salt. In another embodiment,the quaternary alkylammonium salt is a tetraoctylammonumium salt. In yetanother embodiment, the quaternary alkylammonium salt is atrioctylmethylammonumium salt.

Dehydrochlorination of the E-isomer of1,1,1,4,4,4-hexafluoro-2-chloro-2-butene can be effected with quaternaryalkylammonium salts, wherein the alkyl groups are alkyl chains having atleast one alkyl chain of 8 carbons or more. In another embodiment, thequaternary alkylammonium salt has three alkyl chains of 8 carbons ormore, such as trioctylmethylammonium salt. In yet another embodiment,the quaternary alkylammonium salt is a tetraoctylammonumium salt. In yetanother embodiment, the quaternary ammonium salt is a tetradecylammoniumsalt. In yet another embodiment, the quaternary alkylammonium salt is atetradodecylammonium salt. The anions of the salt can be halides such aschloride or bromide, hydrogen sulfate, or any other commonly used anion.

In yet another embodiment, dehydrochlorination of the E-isomer of1,1,1,4,4,4-hexafluoro-2-chloro-2-butene can be effected with quaternaryalkylammonium salts, wherein the alkyl groups are alkyl chains havingfrom four to twelve carbon atoms, and in the presence of a non-ionicsurfactant. The non-ionic surfactants can be ethoxylated nonylphenols,and ethoxylated C12 to C15 linear aliphatic alcohols. Suitable non-ionicsurfactants include Bio-soft® N25-9 and Makon® 10 are from StepanCompany.

In one embodiment, the quaternary alkylammonium salts is added in anamount of from 0.5 mole percent to 2.0 mole percent of the1,1,1,4,4,4-hexafluoro-2-chloro-2-butene. In another embodiment, thequaternary alkylammonium salts is added in an amount of from 1 molepercent to 2 mole percent of the1,1,1,4,4,4-hexafluoro-2-chloro-2-butene. In yet another embodiment, thequaternary alkylammonium salts is added in an amount of from 1 molepercent to 1.5 mole percent of the1,1,1,4,4,4-hexafluoro-2-chloro-2-butene.

In one embodiment, the dehydrochlorination of Z- orE-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene is conducted in the presenceof an alkali metal halide salt. In one embodiment, the alkali metal issodium or potassium. In one embodiment, the halide is chloride orbromide. In one embodiment, the alkali metal halide salt is sodiumchloride. Without wishing to be bound by any particular theory, it isbelieved that the alkali metal halide salt stabilizes the phase transfercatalyst. Although the dehydrochlorination reaction itself producesalkali metal chloride, and in particular sodium chloride if sodiumhydroxide is used as the base, addition of extra sodium chlorideprovides a further effect of increasing the yield ofhexafluoro-2-butyne.

Addition of alkali metal halide salt also reduces the amount of fluorideion measured in the water effluent from the reaction. Without wishing tobe bound by any particular theory, the presence of fluoride is believedto result from decomposition of either the1,1,1,4,4,4-hexafluoro-2-chloro-2-butene starting material, or thehexafluoro-2-butyne product.

In several samples, the amount of fluoride ion found in the watereffluent from the dehydrochlorination is about 6000 ppm. In severalexamples, using from 30 to 60 equivalents of sodium chloride per mole ofphase transfer catalyst, the amount of fluoride ion in the watereffluent is reduced to 2000 ppm. In one embodiment, the alkali metalhalide is added at from 25 to 100 equivalents per mole of phase transfercatalyst. In another embodiment, the alkali metal halide is added atfrom 30 to 75 equivalents per mole of phase transfer catalyst. In yetanother embodiment, the alkali metal halide is added at from 40 to 60equivalents per mole of phase transfer catalyst.

In one embodiment, the reaction is conducted at a temperature of fromabout 60 to 90° C. In another embodiment, the reaction is conducted at70° C.

As used herein, the basic aqueous solution is a liquid (whether asolution, dispersion, emulsion, or suspension and the like) that isprimarily an aqueous liquid having a pH of over 7. In some embodiments,the basic aqueous solution has a pH of over 8. In some embodiments, thebasic aqueous solution has a pH of over 10. In some embodiments, thebasic aqueous solution has a pH of 10-13. In some embodiments, the basicaqueous solution contains small amounts of organic liquids which may bemiscible or immiscible with water. In some embodiments, the liquidmedium in the basic aqueous solution is at least 90% water. In oneembodiment the water is tap water; in other embodiments the water isdeionized or distilled.

The base in the aqueous basic solution is selected from the groupconsisting of hydroxide, oxide, carbonate, or phosphate salts of alkali,alkaline earth metals and mixtures thereof. In one embodiment, baseswhich may be used lithium hydroxide, sodium hydroxide, potassiumhydroxide, calcium hydroxide, magnesium oxide, calcium oxide, sodiumcarbonate, potassium carbonate, sodium phosphate, potassium phosphate,or mixtures thereof.

Step IV

In one embodiment, the process is a method for the synthesis ofZ-HFO-1336mzz from hexafluoro-2-butyne in high selectivity by selectivehydrogenation in the presence of particular catalysts.

In one embodiment, the catalyst is a Palladium catalyst dispersed onaluminum oxide or titanium silicate, doped with silver and/or alanthanide, with a low loading of palladium. In one embodiment, thepalladium loading is from 100 ppm to 5000 ppm. In another embodiment,the palladium loading is from 200 ppm to 5000 ppm. In one embodiment,the catalyst is doped with at least one of silver, cerium or lanthanum.In one embodiment, the mole ratio of cerium or lanthanum to palladium isfrom 2:1 to 3:1. In one embodiment the mole ratio of silver to palladiumis about 0.5:1.0.

In another embodiment, a Lindlar catalyst is used, which is aheterogeneous palladium catalyst on a calcium carbonate support, whichhas been deactivated or conditioned with a lead compound. The leadcompound can be lead acetate, lead oxide, or any other suitable leadcompound. In one embodiment, the catalyst is prepared by reduction of apalladium salt in the presence of a slurry of calcium carbonate,followed by the addition of the lead compound. In one embodiment, thepalladium salt is palladium chloride. In another embodiment, thecatalyst is deactivated or conditioned with quinoline. In oneembodiment, the amount of the catalyst used is from about 0.5% by weightto about 4% by weight of the amount of the fluorinated alkyne. Inanother embodiment, the amount of the catalyst used is from about 1% byweight to about 3% by weight of the amount of the fluorinated alkyne. Inyet another embodiment, the amount of the catalyst used is from about 1%to about 2% by weight of the amount of the fluorinated alkyne.

In one embodiment, the process is conducted in a batchwise process. Inanother embodiment, the process is conducted in a continuous process inthe gas phase.

In one embodiment, reaction of the fluorinated alkynes withhydrogenation in the presence of the catalyst should be done withaddition of hydrogen in portions, with increases in the pressure of thevessel of no more than about 100 psi with each addition. In anotherembodiment, the addition of hydrogen is controlled so that the pressurein the vessel increases no more than about 50 psi with each addition. Inone embodiment, after enough hydrogen has been consumed in thehydrogenation reaction to convert at least 50% of the fluorinated alkyneto alkene, hydrogen can be added in larger increments for the remainderof the reaction. In another embodiment, after enough hydrogen has beenconsumed in the hydrogenation reaction to convert at least 60% of thefluorinated alkyne to alkene, hydrogen can be added in larger incrementsfor the remainder of the reaction. In yet another embodiment, afterenough hydrogen has been consumed in the hydrogenation reaction toconvert at least 70% of the fluorinated alkyne to alkene, hydrogen canbe added in larger increments for the remainder of the reaction. In oneembodiment, the larger increments of hydrogen addition can be 300 psi.In another embodiment, the larger increments of hydrogen addition can be400 psi.

In one embodiment, the amount of hydrogen added is about one molarequivalent per mole of fluorinated alkyne. In another embodiment, theamount of hydrogen added is from about 0.9 moles to about 1.3 moles, permole of fluorinated alkyne. In yet another embodiment, the amount ofhydrogen added is from about 0.95 moles to about 1.1 moles, per mole offluorinated alkyne. In yet another embodiment, the amount of hydrogenadded is from about 0.95 moles to about 1.03 moles, per mole offluorinated alkyne.

In one embodiment, the hydrogenation is performed at ambienttemperature. In another embodiment, the hydrogenation is performed atabove ambient temperature. In yet another embodiment, the hydrogenationis performed at below ambient temperature. In yet another embodiment,the hydrogenation is performed at a temperature of below about 0° C.

In an embodiment of a continuous process, a mixture of fluorinatedalkyne and hydrogen are passed through a reaction zone containing thecatalyst. In one embodiment, the molar ratio of hydrogen to fluorinatedalkyne is about 1:1. In another embodiment of a continuous process, themolar ratio of hydrogen to fluorinated alkyne is less than 1:1. In yetanother embodiment, the molar ratio of hydrogen to fluorinated alkyne isabout 0.67:1.0.

In one embodiment of a continuous process, the reaction zone ismaintained at ambient temperature. In another embodiment of a continuousprocess, the reaction zone is maintained at a temperature of 30° C. Inyet another embodiment of a continuous process, the reaction zone ismaintained at a temperature of about 40° C. In yet another embodiment ofa continuous process, the reaction zone is maintained at a temperatureof from 60° C. to 90° C.

In one embodiment of a continuous process, the flow rate of fluorinatedalkyne and hydrogen is maintained so as to provide a residence time inthe reaction zone of about 30 seconds. In another embodiment of acontinuous process, the flow rate of fluorinated alkyne and hydrogen ismaintained so as to provide a residence time in the reaction zone ofabout 15 seconds. In yet another embodiment of a continuous process, theflow rate of fluorinated alkyne and hydrogen is maintained so as toprovide a residence time in the reaction zone of about 7 seconds.

It will be understood, that contact time in the reaction zone is reducedby increasing the flow rate of fluorinated alkyne and hydrogen into thereaction zone. As the flow rate is increased this will increase theamount of fluorinated alkyne being hydrogenated per unit time. Since thehydrogenation is exothermic, depending on the length and diameter of thereaction zone, and its ability to dissipate heat, at higher flow ratesit may be desirable to provide a source of external cooling to thereaction zone to maintain a desired temperature.

In one embodiment of a continuous process, the mixture of fluorinatedalkyne and hydrogen further comprises an inert carrier gas. In oneembodiment, the inert carrier gas is selected from the group consistingof nitrogen, helium or argon. In one embodiment, the inert carrier gasis from about 10% to about 80% of the gas fed to the continuous process.In another embodiment, the inert carrier gas is from about 20% to about50% of the gas fed to the continuous process.

In one embodiment of a continuous process, the amount of palladium onthe support in the Lindlar catalyst is 5% by weight. In anotherembodiment, the amount of palladium on the support in the Lindlarcatalyst is greater than 5% by weight. In yet another embodiment, theamount of palladium on the support can be from about 5% by weight toabout 1% by weight.

In one embodiment, upon completion of a batch-wise or continuoushydrogenation process, the cis-dihydrofluoroalkene can be recoveredthrough any conventional process, including for example, fractionaldistillation. In another embodiment, upon completion of a batch-wise orcontinuous hydrogenation process, the cis-dihydrorofluoroalkene is ofsufficient purity to not require further purification steps.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

Also, use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of embodiments of the present invention, suitablemethods and materials are described below. All publications, patentapplications, patents, and other references mentioned herein areincorporated by reference in their entirety, unless a particular passageis cited. In case of conflict, the present specification, includingdefinitions, will control. In addition, the materials, methods, andexamples are illustrative only and not intended to be limiting.

EXAMPLES

The concepts described herein will be further described in the followingexamples, which do not limit the scope of the invention described in theclaims.

Example 1

Example 1 demonstrates the preparation of a ruthenium catalyst supportedon silicon carbide from ruthenium chloride.

In this experiment, fifty grams (50 gm) of SiC support is added to 2.632gm of RuCl₃(H₂O)₃ in just enough water to wet the SiC. The sample ismixed using a vortexer at a 1400 speed setting. Vortex the mixture for15-20 seconds then allow to set for 5 minutes. This will be repeatedseveral times over a period of 30-60 minutes, until all excess water isabsorbed. Allow the sample to air dry inside the beaker for an hourbefore removing the sample and placing on a screen to air dry. Once thesample is visibly air dried, place it inside a quartz boat and in thefurnace. Heat to 125° C. for 4 hours, then 250° C. for 4 hours undernitrogen.

Example 2

Example 2 demonstrates the preparation of a ruthenium catalyst supportedon silicon carbide from ruthenium nitrosyl nitrate.

In this experiment, fifty grams (50 gm) of SiC support is added to 3.208gm of Ru(NO)NO₃ and 1.42 gm of triethanolamine in just enough water towet the SiC. The sample is mixed using a vortexer at a 1400 speedsetting. Vortex the mixture for 15-20 seconds then allow to set for 5minutes. This will be repeated several times over a period of 30-60minutes, until all excess water is absorbed. Allow the sample to air dryinside the beaker for an hour before removing the sample and placing ona screen to air dry. Once the sample is visibly air dried, place itinside a quartz boat and in the furnace. Heat to 125° C. for 4 hours,then 250° C. for 4 hours under nitrogen.

Example 3

Example 3 demonstrates the conversion of 113a to 1316mxx over 1% Ru/SiCcatalyst.

An inconel tube (½ inch OD) was filled with 2 cc (1.07 gm) of 1% Ru/SiC⅛″ pellets. The temperature of the catalyst bed was raised to 120° C.and purged with hydrogen (50 sccm) for 60 minutes and then at 250° C.for 180 minutes. The temperature was then lowered to 175° C. for 120minutes while maintaining a hydrogen flow of 20 sccm. The temperaturewas lowered to 160° C. and the flow of CFC-113a (CF₃CCl₃) set to 2.31ml/hour and the hydrogen to 32 sccm. The reactor effluent was analyzedevery hour via online GCMS and then the results averaged to give thevalues in the table below. The temperature was raised to 170° C. and theeffluent analyzed every hour for four hours, averaged, and shown in thetable below.

TABLE 1 % % % % % % % Temp 143a 114a 123 113a Z-1316 E-1316 316maa (°C.) 4.1 2.1 2.8 60 18.4 11.7 0.3 160 4.9 2.2 2.8 57.4 19.6 12.0 0.4 170

Example 4

Example 4 demonstrates the conversion of 113a to 1316mxx over 2% Rucatalyst.

An inconel tube (½ inch OD) was filled with 2 cc (1.07 gm) of 2% Rusupported on ⅛″ pellets either on SiC or CaF₂. The temperature of thecatalyst bed was raised to 120° C. and purged with hydrogen (50 sccm)for 60 minutes and then at 250° C. for 180 minutes. The temperature wasthen lowered to 175° C. for 120 minutes while maintaining a hydrogenflow of 20 sccm. The temperature was lowered to 160° C. and the flow ofCFC-113a (CF₃CCl₃) set to 2.31 ml/hour and the hydrogen to 32 sccm. Thereactor effluent was analyzed every hour via online GCMS and then theresults averaged to give the values in the table below. The temperaturewas raised to 170° C. and the effluent analyzed every hour for fourhours, averaged, and shown in the table below.

TABLE 2 % % % % % % % Temp Support 143a 114a 123 113a Z-1316 E-1316316maa (° C.) SiC 1.9 2.0 1.3 53.0 24.0 16.7 0.6 160 SiC 2.7 2.1 1.745.5 28.8 17.9 0.7 170 CaF₂ 0.8 2.2 2.7 59.5 22.8 10.9 1.0 160 CaF₂ 0.82.1 2.2 55.5 25.2 12.1 1.3 170

Example 5

Example 5 demonstrates the conversion of CFC-1316mxx to HFC-1326mzz overPd/Cu on carbon catalyst.

An Inconel® tube (⅝ inch OD) was filled with 13 cc (5.3 gm) of Pd/Cu onacid washed carbon (18-30 mesh). The temperature of the reactor wasraised to 100° C. for 30 minutes under N₂ flow (30 sccm, 5.0×10⁻⁷m³/sec). The temperature was then increased to 200° C. under H₂ flow forone hour. The catalysts and flows were changed as described in theexperiments in Table 3, below, and the reactor effluent was analyzed byGCMS to provide the following molar percent of products.

TABLE 3 Molar ratio CT H₂/ Reactor effluent concentration (molar %)Catalyst (sec) 1316 t-1336 356mff 1345 c-1336 346mdf 1316mxx 1326Pd/Cu/C 30 2:1 0.17 0 0 0.09 0.13 46.31 52.98 Pd/CaF2 30 2:1 4.8 9.3 013.2 2.3 53.5 11.4

Example 6

Example 6 demonstrates the conversion of CFC-1316mxx to HFC-1336mzz withPd/Cu on carbon catalyst.

A Hastelloy reactor 10″L×½″ o.d.×0.034″ wall was filled with 11 cc ofthe catalyst. The catalyst was conditioned at 150° C. for 65 hrs inhydrogen flow of 50 sccm (8.3×10⁻⁷ m³/sec). The hydrodechlorination of1316mxx was studied at temperatures of 240° C. using Pd/Cu on carbon orPd/BaCl2 on alumina, as indicated in Table 4. Products of the reactionwere analyzed by GCMS to give the following molar concentrations.

TABLE 4 Molar ratio CT H₂/ Reactor effluent concentration (molar %) Cat.(sec) 1316mxx t-1336 1345 356mff c-1336 t-1326mxz c-1326mxz t-1316mxxc-1316mxx Pd/Cu/C 30 1:1 5.1 0 0.43 0.58 69.35 5.75 7.64 5.31 Pd/BaCl230 1:1 11.39 0.57 7.81 1.13 20.35 0.64 49.21 1.79

Example 7

Example 7 demonstrates the effect of catalyst on degree of conversion ofE- and Z-1326mxz.

A Hastelloy reactor 5″L×½″ o.d.×0.034″ wall was filled with 3 cc ofeither 0.6% Pd/5.5% Cu/C, or Ni/Cu/C catalyst. The catalyst wasconditioned at 150° C. for 65 hrs in hydrogen flow of 50 sccm (8.3×10⁻⁷m³/sec).

Example 8

Example 8 demonstrates the conversion of CFC-1316mxx to HFC-1336mzz overCu on carbon catalyst.

In a 400 ml Pyrex beaker a solution of 10.73 g CuCl₂·2H₂O was preparedin 65 ml of 10% HCl in deionized water. 46.0 g of acid washed carbon(10/30 mesh) was added to the solution. The stiff slurry was allowed tostand at room temperature for 1 hr with occasional stirring. Then theslurry was dried at 110-120° C. under air overnight. After that thecatalyst was transferred into quartz tube which was purged with 500 sccm(8.3×10⁻⁶ m³/sec) N₂ at 25° C. for 15 min, then 100 sccm each He and H₂for 15 min. Then the catalyst was heated at 5° C./min to 500° C. for 6hrs in He/H₂. The procedure gave 48.52 g of catalyst.

A Hastelloy reactor 10″L×½″ o.d.×0.034″ wall was filled with 11 cc (4.73g) of 8% Cu on acid washed carbon catalyst. The catalyst was conditionedat 150° C. for 16 hrs in hydrogen flow of 50 sccm (8.3×10⁻⁷ m³/sec). Thetemperature was raised to 350° C. for 2 hrs in hydrogen flow of 50 sccm(8.3×10⁻⁷ m³/sec). The hydrodechlorination of 1316mxx was studied attemperatures ranging from about 300 to 400° C. as indicated in Table 5,below. Products of the reaction were analyzed by GCMS to give thefollowing molar concentrations.

TABLE 5 Reactor effluent concentration (molar %) Molar ratio Temp CT H₂/t- c- t- c- ° C. (sec) 1316 t-1336 1345 356mff c-1336 1326mxz 1326mxz1316mxx 1316mxx 300 30 4:1 0.58 0.0 0.40 0.09 31.47 1.65 34.41 29.85 30060 4:1 1.65 0.0 1.18 0.12 73.93 4.16 5.16 11.72 340 60 4:1 27.34 0.060.90 1.38 66.35 2.87 0.0 0.0 340 75 5:1 56.81 1.18 3.42 3.25 32.00 1.140.0 0.0 325 75 5:1 35.80 0.66 2.62 2.63 53.64 2.05 0.0 0.0 360 75 5:168.83 2.54 5.14 3.21 17.76 0.63 0.0 0.0 360 75 5:1 66.08 2.63 5.27 3.3919.91 0.68 0.0 0.0 400 75 5:1 65.00 9.13 17.40 2.10 0.48 0.00 0.0 0.0400 50 5:1 69.78 5.93 8.94 4.39 7.07 0.08 0.0 0.0

Example 9

Example 9 demonstrates the conversion of CFC-1316mxx to HFC-1336 overCu/Ni on carbon catalyst.

A Hastelloy reactor 15″L×1″ o.d.×0.074″ wall was filled with 23 cc (8.7g) of 1% Cu/1% Ni on carbon catalyst. The catalyst was conditioned with50 sccm (8.3×10⁻⁷ m³/sec) of hydrogen flow according to the followingprotocol: 1 hr at 50° C., followed by 1 hr at 100° C., followed by 1 hrat 150° C., followed by 1 hr at 200° C., followed by 1 hr at 250° C.,followed by 2 hr at 300° C., followed by a final 16 hrs at 200° C.

The hydrodechlorination of 1316mxx was studied over a temperature rangeof 200-375° C. Products of the reaction were analyzed by GCMS to givethe molar concentrations as listed in Table 6.

TABLE 6 Molar Reactor effluent concentration (molar %) Temp CT ratio t-c- t- c- t- c- ° C. (sec) H₂/1316 1336 1336 1326mxz 1326mxz 1316mxx1316mxx 200 75   5:1 0.14 0.47 40.50 1.24 51.34 5.38 300 75   5:1 7.100.61 87.28 3.91 0.08 0.12 300 75 7.5:1 34.31 4.04 58.68 1.64 0.00 0.00350 30 7.5:1 60.33 6.51 29.96 0.47 0.00 0.00 375 30 7.5:1 75.71 6.988.41 0.05 0.00 0.00

Example 10

Example 10 demonstrates the selective hydrogenation ofhexafluoro-2-butyne with Lindlar's catalyst.

5 g of Lindlar (5% Pd on CaCO3 poisoned with lead) catalyst was chargedin 1.3 L rocker bomb. 480 g (2.96 mole) of hexafluoro-2-butyne wascharged in the rocker. The reactor was cooled down (−78° C.) andevacuated. After the bomb was warmed up to room temperature, H₂ wasadded slowly, by increments which did not exceed Δp=50 psi. A total of 3moles H₂ were added to the reactor. A gas chromatographic analysis ofthe crude product indicated the mixture consisted of CF₃C≡CCF₃ (0.236%),trans-isomer of CF₃CH═CHCF₃ (0.444%), saturated CF₃CH₂CH₂CF₃ (1.9%)CF₂═CHCl, impurity from starting butyne, (0.628%), cis-isomer ofCF₃CH═CHCF₃ (96.748%). Distillation afforded 287 g (59% yield) of 100%pure cis-CF₃CH═CHCF₃ (boiling point 33.3° C.).

Example 11

Example 11 demonstrates the hydrogenation of hexafluoro-2-butyne over acatalyst of 200 ppm Pd on alumina, and doped 3:1 with cerium.

A Hastelloy tube reactor 8″ long with a 1″ O.D. (outside diameter) and0.074″ wall thickness was filled with 3 g of catalyst. The catalyst wasconditioned at 70° C. with a flow of nitrogen (50 sccm) and hydrogen (10sccm) for one hour at 200 C. The reactor was cooled to 82 C. A mixtureof hexafluoro-2-butyne (5.5 sccm), hydrogen (1.6 sccm) and nitrogen (454sccm) were then flowed into the reactor with a back pressure of 50 psig.The product mixture was collected in a cold trap after exiting thereactor and analyzed by gas chromatography. The product mixture wasfound to contain CF₃CH═CHCF₃ (cis) (36.5%), CF₃CH═CHCF₃ (trans) (1.6%),CF₃CH₂CH₂CF₃ (0.43%) and unreacted CF₃C≡CCF₃ (60.8%).

Example 12

Example 12 demonstrates the hydrogenation of hexafluoro-2-butyne over acatalyst of 200 ppm Pd on alumina, and doped 2:1 with lanthanum.

A Hastelloy tube reactor 8″ long with a 1″ O.D. (outside diameter) and0.074″ wall thickness was filled with 3 g of catalyst. The catalyst wasconditioned at 70° C. with a flow of nitrogen (50 sccm) and hydrogen (10sccm) for one hour at 200 C. The reactor was cooled to 74 C. A mixtureof hexafluoro-2-butyne (5.8 sccm), hydrogen (2.0 sccm) and nitrogen (455sccm) were then flowed into the reactor with a back pressure of 50 psig.The product mixture was collected in a cold trap after exiting thereactor and analyzed by gas chromatography. The product mixture wasfound to contain CF₃CH═CHCF₃ (cis) (34.3%), CF₃CH═CHCF₃ (trans) (0.95%),CF₃CH₂CH₂CF₃ (0.08%) and unreacted CF₃C≡CCF₃ (64.7%).

Example 13

Example 13 demonstrates the hydrogenation of hexafluoro-2-butyne in acontinuous process to produce a mixture of cis- andtrans-1,1,1,4,4,4-hexafluoro-2-butene.

A Hastelloy tube reactor 10″ long with a 5″ O.D. (outside diameter) and0.35″ wall thickness was filled with 10 g of Lindlar catalyst. Thecatalyst was conditioned at 70° C. with a flow of hydrogen for 24 hours.Then a flow of a 1:1 mole ratio of hexafluoro-2-butyne and hydrogen waspassed through the reactor at 30° C. at a flow rate sufficient toprovide a 30 second contact time. The product mixture was collected in acold trap after exiting the reactor and analyzed by gas chromatography.The product mixture was found to contain CF₃CH═CHCF₃ (cis) (72%),CF₃CH═CHCF₃ (trans) (8.8%), CF₃CH₂CH₂CF₃ (7.8%) and CF₃C≡CCF₃ (3.3%).

Example 14

Example 14 demonstrates the hydrogenation of hexafluoro-2-butyne in acontinuous process with a hydrogen:alkyne mole ratio of 0.67:1.

The procedure of example 13 was followed, with the exception that themole ratio of hydrogen:hexafluoro-2-butyne fed to the reactor was0.67:1.0. Analysis of the product mixture indicated CF₃CH═CHCF₃ (cis)(65.3%), CF₃CH═CHCF₃ (trans) (4.4%), CF₃CH₂CH₂CF₃ (3.4%) and CF₃C≡CCF₃(23.5%).

Example 15

Example 15 demonstrates the hydrogenation of hexafluoro-2-butyne in acontinuous process with a 7 second contact time.

The procedure of example 13 was followed, with the exception that theflow rate was adjusted to provide a contact time of 7 seconds. Thereaction was slightly exothermic, with the reactor warming to 42° C.Analysis of the product mixture indicated CF₃CH═CHCF₃ (cis) (72.5%),CF₃CH═CHCF₃ (trans) (8.7%), CF₃CH₂CH₂CF₃ (8.6%) and CF₃C≡CCF₃ (6.9%).

Example 16

NaOH aqueous solution (12 mL, 0.12 mol) was added to the mixture ofZ-1326 (20 g, 0.1 mol) and water (18 mL) in the presence ofTetra-n-butylammonium bromide (0.45 g, 0.001325 mol) at 35° C. Thereaction temperature was raised to 70° C. after the addition, and gaschromatography was used to monitor the reaction. The reaction wascompleted after 1 hour and 15.4 g product (conversion: 100%; yield: 95%)was collected in a dry ice trap.

Example 17

NaOH aqueous solution (12 mL, 0.12 mol) was added to the mixture ofZ-1326 (20 g, 0.1 mol) and water (18 mL) in the presence of Aliquat® 336(0.53 g, 0.001325 mol) at 35° C. The reaction temperature was raised to70° C. after the addition, and gas chromatography was used to monitorthe reaction. The reaction was completed after 1 hour and 15.6 product(conversion: 100%; yield: 96%) was collected in a dry ice trap.

Example 18

NaOH aqueous solution (12 mL, 0.12 mol) was added to the mixture ofE-1326 (20 g, 0.1 mol) and water (18 mL) in the presence of Aliquat® 336(0.53 g, 0.001325 mol) at 42° C. The reaction temperature was raised to70° C. after the addition, and gas chromatography was used to monitorthe reaction. The reaction was completed after 1 hours and 15.8 gproduct (conversion: 100%; yield: 98%) was collected in a dry ice trap.

Example 19

NaOH aqueous solution (12 mL, 0.12 mol) was added to the mixture ofE-1326 (20 g, 0.1 mol) and water (18 mL) in the presence ofTetraoctylammonium bromide (0.72 g, 0.001325 mol) at 42° C. The reactiontemperature was raised to 70° C. after the addition, and gaschromatography was used to monitor the reaction. The reaction wascompleted after six and half hours. 15.6 g product (conversion: 100%;yield: 95%) was collected in a dry ice trap.

Note that not all of the activities described above in the generaldescription or the examples are required, that a portion of a specificactivity may not be required, and that one or more further activitiesmay be performed in addition to those described. Still further, theorder in which activities are listed are not necessarily the order inwhich they are performed.

In the foregoing specification, the concepts have been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the invention as set forth in theclaims below. Accordingly, the specification and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope ofinvention.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims.

It is to be appreciated that certain features are, for clarity,described herein in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures that are, for brevity, described in the context of a singleembodiment, may also be provided separately or in any subcombination.Further, reference to values stated in ranges include each and everyvalue within that range.

What is claimed is:
 1. A process for the preparation of E- orZ-HF0-1336mzz comprising contacting hexafluoro-2-butyne with hydrogen ata ratio of 1:0.025 to 1:1.1 (molar ratio of hexafluoro-2-butyne in areactor in the presence of a metallic catalyst at a temperaturesufficient to cause hydrogenation of the triple bond of thehexafluoro-2-butyne producing a product stream comprising HFO-1336mzzand unreacted hexafluoro-2-butyne; wherein the catalyst is a metalliccatalyst at a concentration of 100-5000 ppm dispersed over aluminumoxide, silicon carbide, or titanium silicates with a Ag or lanthanidepoison, wherein the recycle ratio of reactant to product is between 1and
 9. 2. The process of claim 1, wherein the lanthanide poison iscerium, lanthanum, or neodymium.
 3. The process of claim 1, wherein thelanthanide poison is at a concentration of 50-1000 ppm.
 4. The processof claim 1, wherein the metallic catalyst is Pd or Pt.
 5. The process ofclaim 1, wherein the metallic catalyst is at a concentration of 100-4900ppm.
 6. The process of claim 2, wherein the metallic catalyst is at aconcentration of 100-3000 ppm.
 7. The process of claim 1, furthercomprising the step of separating at least part of thehexafluoro-2-butyne from the product stream.
 8. The process of claim 7,further comprising the step of recycling the hexafluoro-2-butyne to thereactor.